This invention relates to a communication system for a vehicle.
Vehicles typically have a remote keyless entry system that permits the locking and unlocking of doors as well as the opening and closing of windows. This system has a transmitter located in a key fob or made part of a key that transmits a radio frequency signal to a receiver within the vehicle. Based on signals from the transmitter and received by the receiver, a control unit controls the functioning of the various ports of the vehicle.
Increasingly, manufacturers are installing tire pressure monitoring systems in vehicles. A tire pressure monitoring system provides a vehicle operator with information concerning the tire pressure of the wheels of the vehicle. One common system uses transmitters located at each wheel to transmit information relating to each tire to a receiver on the vehicle. Like remote keyless entry systems, the signal is also transmitted at a radio frequency. However, in contrast to the signal transmitted by the remote keyless entry system, the tire pressure monitoring system transmits its signal on a frequency modulated or FSK band. The signal of the remote keyless entry system (RKE) is transmitted on an amplitude modulated or ASK band.
Due to the differing transmission bands used by each of the systems, a vehicle has two different receivers: one receiver for receiving an amplitude modulated signal and another receiver for receiving a frequency modulated signal. Having a receiver for each system is expensive.
A need therefore exists for a communication system for a vehicle that eliminates the additional receiver.